Like the other commentor- I also tried hard to use wger but it was just too unintuitive. I switched to Liftosaur and love it for making a weight lifting routine easy to design and track:
I did test self hosting it and it's not too bad, but just switched to my iPad and subscribing for the premium because the auto calculating the plates for each lift saves me a lot of time and I feel good supporting this developer.
I use Track & Graph from F-Droid for tracking the amount of workouts and my weight. It's not really specific to fitness or health, but I use for its support for exporting to CSV.